US3826885A - Pushbutton switch having spider-shaped contact contact carrier - Google Patents

Pushbutton switch having spider-shaped contact contact carrier Download PDF

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Publication number
US3826885A
US3826885A US00265452A US26545272A US3826885A US 3826885 A US3826885 A US 3826885A US 00265452 A US00265452 A US 00265452A US 26545272 A US26545272 A US 26545272A US 3826885 A US3826885 A US 3826885A
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US
United States
Prior art keywords
contact
contact element
switch
central portion
making
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00265452A
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English (en)
Inventor
W Allen
W Tomasulo
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Wild Rover Corp
Original Assignee
Wild Rover Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Wild Rover Corp filed Critical Wild Rover Corp
Priority to US00265452A priority Critical patent/US3826885A/en
Priority to GB671873A priority patent/GB1427971A/en
Priority to NL7302401A priority patent/NL7302401A/xx
Priority to DE19732311447 priority patent/DE2311447A1/de
Priority to FR7308888A priority patent/FR2221799B1/fr
Priority claimed from FR7308888A external-priority patent/FR2221799B1/fr
Application granted granted Critical
Publication of US3826885A publication Critical patent/US3826885A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/12—Contacts characterised by the manner in which co-operating contacts engage
    • H01H1/14—Contacts characterised by the manner in which co-operating contacts engage by abutting
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H13/00—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch
    • H01H13/02—Details
    • H01H13/12—Movable parts; Contacts mounted thereon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H13/00—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch
    • H01H13/50—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a single operating member
    • H01H13/52—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a single operating member the contact returning to its original state immediately upon removal of operating force, e.g. bell-push switch
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2235/00—Springs
    • H01H2235/01—Spiral spring

Definitions

  • the contact element includes a central contact-making portion and leg portions flexibly attached thereto that extend partially circumferentially about the central portion and out of the plane of the central portion.
  • the contact element is prebiased by preflexing the legs so that a predetermined threshold force must be exceeded before any movement of the contact-making portion takes place.
  • electrical simultaneity of contact between a plurality of extended, parallel contact segments and a base contact structure is achieved through the use of a relatively rigid diaphragm containing the extended contact segments. Advantages accrue from broad area simultaneity of contact without independence of contacting by the individual contact segments.
  • the diaphragm is supported by a resilient leg structure permitting the diaphragm to move in parallel relation to the base contact structure.
  • the invention involves prebiasing, namely, the preloading of a spring-mounted contact element so that a predetermined threshold force must be exceeded before any movement of the contact element takes place.
  • prebiasing has the advantage of minimizing force variations from switch to switch due to gross imprecision in contact separations.
  • a spring structure which has polar symmetry.
  • a contact-making structure comprising a plurality of physically parallel and extended contact segments.
  • the orientation of the extended contact segments is correlated with the polar symmetrical structure to provide an overall spring element contact-making structure which is stable in operation and which tends to self-correct for offcenter forces applied to this structure.
  • Woodhead does nothing to correlate the contact-making portion of his movable element with the spring portion of his element.
  • the orientation of the extended contact segments provides for unique stability in operation.
  • a relatively rigid contact making structure is utilized in the diaphragm-type element of the present invention in order to provide for proper orientation of the contact-making segments as they make contact with the fixed base contacts, a factor unappreciated by Woodhead.
  • Representative prior art patents are as follows:
  • FIGS. 1 and 2 are perspective views of a capsule-type switch embodying the invention.
  • the switch of the normally off momentarily on type (the switch is in the on state as long as an actuating force is applied), is shown in exploded view in FIG. 6, and involves only four parts, namely, a housing 22, an energy directing actuating element 24, a contact element 26 and a base structure 28 that includes two base contacts 30 and 32 connected to output terminals 34 and 36.
  • the housing 22 is advantageously formed with two shoulders or ledges 22a and 22b, as well as with a slot 22d in the side thereof.
  • the housing 22 is open at both ends thereof. As shown in FIG.
  • the energy directing actuating element 24 is positioned within the housing 22 so that an annular shoulder 24a thereof is seated upon housing ledge 22a.
  • the outwardly directed surface 24b of the energy directing actuator element 24 is flush with the lower annular outwardly directed surface 222 of the switch housing 22 in the non-actuated state of the switch, as shown in FIG. 3.
  • the energy director 24 includes a dimpled portion 240 that is positioned on the side thereof opposite from the outer surface 24b. The dimpled portion 240 serves to concentrate energy in the actuation of the switch in the center of the contact element 26, to be explained in more detail below.
  • the contact element 26 is shown. It is a diaphragm-type element that includes a central portion 26a and a plurality of legs 26b, 26c and 26d flexibly attached to the central portion 26a.
  • the leg portions 26b extend partially circumferentially about the central portion 26a and, in the unstressed or unflexed state thereof, out of the plane of the central portion, as shown in FIG. 5.
  • the leg portions include feet portions thereof, designated 26e, 26f and 26g.
  • the feet portions may be dimpled, e.g., semi-spherical in shape, to reduce friction in the action of the spring 26, to be described in more detail below.
  • the central portion 260 of the contact element includes a plurality-of linearly extending contact-making segments .2611
  • These segments may be constituted of wires affixed to a plate 261' that is in turn affixed to the central portion 26a of the contact element.
  • the leg portions 26b, 26c and 26d of the contact element extend partially circumferentially about the central portion 26a.
  • Each leg portion subtends an are approximately 90 in the form shown in FIG. 4, although a 90 arc is not critical and the arc may differ from 90,and the leg portions are equiangularly spaced about the central portion 26a of the contact element.
  • the leg portions of the contact element exhibit polar symmetry about the central portion.
  • the feet portions 26e, 26f and 26g thereof are angularly spaced from each other by 120.
  • the regions at which the leg portions are joined to the central portion, designated 26j, 26k and 26m in FIG. 4, are also angularly speaced from each other by 120.
  • the feet portions 26e, 26f and 26g are located at the ends of the corresponding leg portions and are unattached to the central portion 26a of the contact element. While this construction is preferred, it is possible to include the leg portions as part of a continuous ring of material (not shown) constituting the leg portions, which ring of material is attached to the central portion of the contact element at angularly spaced regions of connection. Such a continuous ring leg portion structure would provide a stiffer diaphragm-type spring element. Further, it should be noted that the stiffness of the contact element may be varied by variation of the material of the element and its thickness, as well as by variation of the circumferential extend of the leg portions.
  • leg portions Shorter leg portions, in the sense that they each extend over less of an angular segment than do the 90 leg portions shown specifically in FIG. 4, would tend to provide a relatively stiffer spring action in the contact element.
  • the curvature of the leg portions may be in the form of an arc of a circle, as in the presently preferred embodiment, or they may range in curvature from that shape to straight line segments, all as viewed in plan. 7
  • leg portions While three leg portions have been utilized in the presently preferred embodiment switch, it should be noted that a different number of leg portions may be employed. It is believed that an odd number of leg portions should be utilized, exhibiting polar symmetry with respect to the central portion 26a.
  • the linearly extending contact-making segments 26h that are affixed to the central portion 26a of the contact element provide a stiffening of that portion of the contact element.
  • the contact element is typically made of beryllium copper, and is relatively flexible.
  • the contact segments 26h as well as the plate 261' upon which they are affixed provides a stiffening of the central portion 26a so that it is relatively regid. Nonetheless, the entire contact element 26 is flexible, and exhibits a definite spring action by virtue of the flexing of the leg portions 26b, 26c and 26d.
  • the orientation of the linearly extending, physically parallel contact-making segments 26h is believed to be important. In particular, it is presently preferred to have such contact-making segments extend in lines that are parallel to a line between the center of the central portion 26a and one of the feet portions of the contact element. In particular, in the contact element 26 shown in FIG. 4, the segments 26h are parallel to a line between the center of the central portion 26a and the foot portion 26f. Such orientation of contact-making segments is believed advantageously to compensate for off center actuation of the contact element by the energy director 24, to be explained in more detail below.
  • the contact element 26 is mounted within the switch housing 22 as shown in FIG. 3, so that the feet portions 26e, 26f and 26g ride upon the surface 28a of the base element 28. As shown in FIG. 3, which is the nonactuated state of the switch 20, the contact element 26 is in a prebiased or bowed state in which the leg portions 26b, 26c and 26d are flexed from the unlfexed state shown in FIG. 5.
  • the distance between the feet portions of the contact element and the central portion in the unflexed state may be approximately 0.070 inch, while in the flexed state shown in FIG. 3 the same distance may be approximately 0.040 inch.
  • the contact element 26 may be maintained in place within the housing through use of an extension 26n of one of the leg portions which fits into the corresponding groove 22d of the housing 22.
  • the assembly of the housing is completed by the positioning of the base structure 28 against the ledge 22b.
  • a tab 28b fits within housing groove 22d to properly position the base structure so that the base contacts 30 and 32 are bridged by the contact-making segments 26h when the switch is actuated.
  • the lower part 22f of the housing may be bent over as shown in FIG. 3 to maintain the switch in assembled condition.
  • FIG. 6A That figure is a force/deflection diagram for the contact element 26 in both unassembled and assembled form.
  • the curve segment designated 40 represents the force/deflection characteristic of the unassembled contact element.
  • the permanent preload or deflection given the leg portions is represented in FIG. 6A by the point designated 42.
  • the initial flexing of the leg portions may be such that the feet portions move 0.035 inch from the unflexed position shown in FIG. 5.
  • This amount of prebiasing or initial flexing corresponds to a force of about 30 grams, for example.
  • this initial prebiasing or threshold force (of 30 grams, for example) must be exceeded. In other words no movement of the central portion 26a that carries the contact-making segments 2612 will take place toward the base contacts 30 and 32 until the predetermined threshold force has been exceeded.
  • the heavily inked curve portion designated 44 in FIG. 6A representes the force/deflection characteristic of the assembled contact element 26 and hence of the switch shown in FIG. 3.
  • the segment 44a represents the initial prebias, and any force applied to the energy directing element 24 from up to about 30 grams in the example will result in no deflection of the contact element.
  • the contact-making segments 26h may be spaced by a distance of about 0.005 inch from fixed base contacts 30 and 32. For this separation, to provide for contact between the contact-making segments and the base contacts an additional or incremental force of grams, for example, is required. After such contact is made, the application of additional force to the energy directing element 24 will result in no further movement of the central portion 26a of the contact element. This is represented in FIG. 6A by the curve segment 44c.
  • Equation 2 may be rewritten in the following form, substituting from equation (1):
  • Equation 3 expresses the percent variation in applied force as a function of the percent variations in displacement and spring constant. Assume as an example that the displacement Z is 5 mils i 2 mils. Accordingly, dz/Z 2/5 40 percent; If k is approximately equal to 10 grams per mil i /2 gram per mil, then dke/ke /z/l0 5 percent. Accordingly, the variation in applied force in such a switch is as much as 45 percent (Spercent plus 40 percent). Where the applied force is normally in the neighborhood of 50 grams, for example, the 45 percent variation possible means that actuation in some applications may be as little as 27.5 grams and as high as 72.5 grams, with actuation of the switch varying between these limits. This is very wide possible variation, which has been experimentally observed in switches, and is unsatifactory from the standpoint of providing switches presenting uniform actuating characteristics to a user.
  • F is the applied force
  • F b is the prebias force (the prebias of 5 grams, for example, shown in FIG. 6A)
  • k is the spring constant of the precompressed spring
  • Z is the deflection of the central portion 26 of the diaphragm-type spring, considering the prebiased position of the central portion as shown in FIG. 3 to be Z 0.
  • dF dF,, kedZ Zdke 5 Equation (5) may be rewritten as follows, substituting from equation (4): dF/F dF kedZ Zdke/F keZ 6 Equation (6) is subject to the following approximation in those cases where the term k Z is much less than F,, (i.e., the incremental applied force necessary to actuate the switch is much less than the prebiasing force) Approximation (7) utilizes the following approximation, which also depends upon the stated relationship between prebias and incremental actuating forces:
  • the variation in applied force as a percentage is roughly 9 percent in the case of a prebiased spring, where, for the same approximate switch parameters subject to the same variations in a non-prebiased switch a 45 percent variation in applied force is possible. This results in a 5:1 suppression of the variations in contact spacing that may occur from switch to switch, even with a 5 percent variation in prebias.
  • precompression or threshold force F0
  • incremental force k,.Z
  • the feet portions 26e, 26f and 26g rest upon the base surface 2811.
  • An additional ring (not shown) may be employed, if desired, upon which the feet portions rest.
  • the semi-spherical shape of the feet portions reduces friction during movement of the central portion 260 of the contact element. It will be noted that there is a slight spacing between the edges of the leg portions of the contact element and the walls of the housing 22, which permits movement of the leg portions to take place. This further allows an optimally soft equivalent spring action which is required to enable a relatively rigidtranslation of the diaphragm or central contact portion 26a.
  • the central portion 26a of the contact element 26 moves rectilinearly, which movement is enhanced by the stiffening of the central portion 26a by the contact segments 26h.
  • the preferred orientation of the contact-making segmens is as shown in FIG. 4 and described above, namely, parallel to a line between the center of the central portion 26a and one of the feet portions (26]). It is believed that such an orientation of the contactmaking segments overcomes the effect of wandering of the energy directing dimple 24c from the centerpoint of the central region 26a of the contact element. Such wandering of the energy directing dimple produces an off-center force which tends to urge the central portion 26a of the contact element to move in other than rectilinear fashion.
  • the transverse (X-X) is the direction in which an enhanced tilting effect toward the center or stiffness with respect with respect to tilting in that direction is achieved.
  • the lon- 9 gitudinal direction (YY) is the direction in which contact tilt is not significant due to near simultaneity of contact closure as in a knife blade switch action.
  • the closure of the contact in that plane exhibits the near angular simultaneity and broadness of area contact within arcing times and capacitive effects.
  • a diaphragm type contact element for a switch comprising a substantially planar central portion, said central portion including a plurality of linearly extending and substantially parallel contact-making segments, and a plurality of leg portions each flexibly joined to said central portion and extending partially circumferentially about said central portion.
  • a contact element according to claim 2 including a plate to which said wires are affixed, and said plate is affixed to said central portion.
  • each leg portion includes a foot portion adapted to support said contact element, and in which said contactmaking segments are substantially parallel to a line between the center of said central portion and one of said feet portions.
  • each of said leg portions extends out of the plane of said central portion in the unflexed state of said leg portion on the same side of said central portion as said contact-making segments.
  • a switch incorporating a contact element according to claim 10 including means holding said contact element with said feet portions closer to the plane of said central portion than in the non-flexed state of said legportions of prebias said contact element in the nonactuated state of said switch and require a threshold force to be exceeded to actuate said switch.
  • a switch according to claim 14 in which said contact-making segments bridge said base contacts in the on state of the switch and which are positioned in the range of from about 0.003 to about 0.030 inch from said base contacts in the off state of said switch.

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  • Push-Button Switches (AREA)
  • Slide Switches (AREA)
  • Tumbler Switches (AREA)
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US00265452A 1972-06-23 1972-06-23 Pushbutton switch having spider-shaped contact contact carrier Expired - Lifetime US3826885A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US00265452A US3826885A (en) 1972-06-23 1972-06-23 Pushbutton switch having spider-shaped contact contact carrier
GB671873A GB1427971A (en) 1972-06-23 1973-02-12 Electric switch and a movable contact element therefor
NL7302401A NL7302401A (enrdf_load_stackoverflow) 1972-06-23 1973-02-21
DE19732311447 DE2311447A1 (de) 1972-06-23 1973-03-08 Elektrischer schalter
FR7308888A FR2221799B1 (enrdf_load_stackoverflow) 1972-06-23 1973-03-13

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
US00265452A US3826885A (en) 1972-06-23 1972-06-23 Pushbutton switch having spider-shaped contact contact carrier
GB671873A GB1427971A (en) 1972-06-23 1973-02-12 Electric switch and a movable contact element therefor
NL7302401A NL7302401A (enrdf_load_stackoverflow) 1972-06-23 1973-02-21
DE19732311447 DE2311447A1 (de) 1972-06-23 1973-03-08 Elektrischer schalter
FR7308888A FR2221799B1 (enrdf_load_stackoverflow) 1972-06-23 1973-03-13

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US3826885A true US3826885A (en) 1974-07-30

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US00265452A Expired - Lifetime US3826885A (en) 1972-06-23 1972-06-23 Pushbutton switch having spider-shaped contact contact carrier

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US (1) US3826885A (enrdf_load_stackoverflow)
DE (1) DE2311447A1 (enrdf_load_stackoverflow)
GB (1) GB1427971A (enrdf_load_stackoverflow)
NL (1) NL7302401A (enrdf_load_stackoverflow)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3962659A (en) * 1973-10-20 1976-06-08 Nippon Electric Company Limited Electromagnetic switch
FR2476900A1 (fr) * 1980-02-27 1981-08-28 Telephonie Ind Commerciale Bouton-poussoir pour clavier de commande et procede de realisation
US4453052A (en) * 1982-02-23 1984-06-05 David W. Semian Adjustable pressure switch
US4459443A (en) * 1982-12-27 1984-07-10 Cherry Electrical Products Corporation Tactile feedback switch
US4608468A (en) * 1984-12-26 1986-08-26 Motorola, Inc. Hermetically sealed impact switch
US4631378A (en) * 1983-10-31 1986-12-23 Jelco. Co., Ltd. Push button switch
US4924040A (en) * 1986-09-25 1990-05-08 Illinois Tool Works Inc. Electrical switching apparatus
US4943690A (en) * 1989-03-06 1990-07-24 Fifth Dimension, Inc. Position insensitive shock sensor with closure delay
US20040079627A1 (en) * 2002-10-25 2004-04-29 Chieh-Rung Huang Electrical switch
US20110073454A1 (en) * 2009-09-28 2011-03-31 Research In Motion Limited key assembly for an electronic device having a multi-character keycap
US20110094868A1 (en) * 2009-10-26 2011-04-28 Research In Motion Limited Key assembly for an electronic device having a connected keycap

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4331851A (en) * 1980-06-16 1982-05-25 Texas Instruments Incorporated Printed circuit board having data input devices mounted thereon and input devices therefor
US4463237A (en) * 1983-04-13 1984-07-31 Wico Corporation Pushbutton assembly with integral bias means

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3143605A (en) * 1961-08-10 1964-08-04 Edwin S Gaynor Combination push-push and momentary switch
US3582596A (en) * 1968-05-17 1971-06-01 Int Standard Electric Corp Diaphragm pushbutton switches
US3602677A (en) * 1968-12-30 1971-08-31 Wild Rover Corp Switch with particular transverse deflection characteristics and movable contact plate with contact making wires attached
US3619526A (en) * 1968-08-19 1971-11-09 Simplifix Couplings Ltd Pressure-actuated switches
US3676617A (en) * 1970-10-16 1972-07-11 Gen Automotive Specialty Co Switch having spider-shaped contact carrier

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3143605A (en) * 1961-08-10 1964-08-04 Edwin S Gaynor Combination push-push and momentary switch
US3582596A (en) * 1968-05-17 1971-06-01 Int Standard Electric Corp Diaphragm pushbutton switches
US3619526A (en) * 1968-08-19 1971-11-09 Simplifix Couplings Ltd Pressure-actuated switches
US3602677A (en) * 1968-12-30 1971-08-31 Wild Rover Corp Switch with particular transverse deflection characteristics and movable contact plate with contact making wires attached
US3676617A (en) * 1970-10-16 1972-07-11 Gen Automotive Specialty Co Switch having spider-shaped contact carrier

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3962659A (en) * 1973-10-20 1976-06-08 Nippon Electric Company Limited Electromagnetic switch
FR2476900A1 (fr) * 1980-02-27 1981-08-28 Telephonie Ind Commerciale Bouton-poussoir pour clavier de commande et procede de realisation
EP0035189B1 (fr) * 1980-02-27 1984-07-04 LA TELEPHONIE INDUSTRIELLE ET COMMERCIALE TELIC ALCATEL S.A. dite: Bouton-poussoir pour clavier de commande et procédé de fabrication d'un tel bouton-poussoir
US4453052A (en) * 1982-02-23 1984-06-05 David W. Semian Adjustable pressure switch
US4459443A (en) * 1982-12-27 1984-07-10 Cherry Electrical Products Corporation Tactile feedback switch
US4631378A (en) * 1983-10-31 1986-12-23 Jelco. Co., Ltd. Push button switch
US4608468A (en) * 1984-12-26 1986-08-26 Motorola, Inc. Hermetically sealed impact switch
US4924040A (en) * 1986-09-25 1990-05-08 Illinois Tool Works Inc. Electrical switching apparatus
US4943690A (en) * 1989-03-06 1990-07-24 Fifth Dimension, Inc. Position insensitive shock sensor with closure delay
US20040079627A1 (en) * 2002-10-25 2004-04-29 Chieh-Rung Huang Electrical switch
US20110073454A1 (en) * 2009-09-28 2011-03-31 Research In Motion Limited key assembly for an electronic device having a multi-character keycap
US8232485B2 (en) * 2009-09-28 2012-07-31 Research In Motion Limited Key assembly for an electronic device having a multi-character keycap
US8383966B2 (en) 2009-09-28 2013-02-26 Research In Motion Limited Key assembly for an electronic device having a multi-character keycap
US20110094868A1 (en) * 2009-10-26 2011-04-28 Research In Motion Limited Key assembly for an electronic device having a connected keycap
US8183478B2 (en) * 2009-10-26 2012-05-22 Research In Motion Limited Key assembly for an electronic device having a connected keycap
US8698018B2 (en) 2009-10-26 2014-04-15 Blackberry Limited Key assembly for an electronic device having a connected keycap

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Publication number Publication date
GB1427971A (en) 1976-03-10
NL7302401A (enrdf_load_stackoverflow) 1974-08-23
DE2311447A1 (de) 1974-09-19

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